Tube rolling apparatus



Aug. 15, 1933.

R K. HOPKINS TUBE ROLLING APPARATUS Filed Sept. 12, 1930 2 Sheets-Sheet 1 R. K. HOPKINS TUBE ROLLING APPARATUS Aug. 15, 1933.

Filed Sept. 12, 1930 2 Sheets-Sheet 2 Patented Aug. 15, 1933 v UNITED STATES PATENT OFFICE TUBE ROLLING APPARATUS Robert K. Hopkins, St. George, Staten Island, N. Y., aeeignor to The M. W. Kellogg Company, New York, N. Y., a Corporation of Delaware Application September 12, 1930 i Serial No. 481,392

Claim]. (Cl- 80-5) This invention relates to the manufacture of and if all ingots .were homogeneous, acertain seamless tubes and hollow bodies particularly by calculated camber on one or more of the rolls internal and external rolling. together with the application of certain definite Ordinarily in rolling seamless tubes on a 03 1- and constant rolling pressures would result in a 5 inder rolling mill a. hollow ingot which has prevl perfect seamless tube. This, however, is an ideal ously been heated to the proper forging temperacondition and one which cannot be expected in ture is positioned on a main roll and h ld i a normal practice for the reason that all ingots are central position by auxiliary centering rolls adnot r ly homogeneous. and olsofor h reason lament the main roll. Another roll smaller than at t e tempe ature at which olli s is carried to the main roll is passed through the hole in the out, contributes another factor which plays an hollow ingot andpositioned for the rolling operimportant part in the deflection of the rolls.

ation adjacent the inner wall of the ingot di- An object of this invention isto roll a hollow rectly opposite the point where the outer ain ingot to form a seamless tube or cylinder in such roll contacts the ingot. In other words, the rolls a m n r h t h fib r elohgetto l n ly are spaced apart by the ingot wall. and at the same rate.

Th m supporting external 11 and t m. Another object of this invention is to obtain a ternal roll are then rotated and the axes of the control for this lli pera n in r r h two rolls are displaced toward each other thus irregularities f0 med during rolling m y be mmaking an impression in the ingot corresponding Penseted a d a true Cylinder ohtelhedto the draft in a normal rolling operation. As Still another obiect o the i v io i to ve y 76 the ingot revolves with the reduction taking place, the section at which the greatest rolling pressure the hot steel is mechanically worked and the cir- 18 applied to an ingot during the rolling P cumference of the ingot increases in length thus I have found that y using a embered int rnal as increasing the diameter of the ingot. This operroll d by regulating t rollin pressu e, that ation is continued until the ingot has reached the is, the pressure of the leree external r011 against desired size, the relatively small internal roll, the fiexure of Th du m in um m of this h the internal roll may be controlled at will so that acter is that it is practically impossible to keep if desired the ereetest Pressure may be applied all fibers along the length of the ingot elongatat whim oi the tube by applying a Pressure ing at the same rate and unless this is done the which is not quite suiiicieht hex an the finished t 11 not be of t cy1mdr1ca1shape her from the roll. Constant pressure over the If more rolling is done in the center of the tube entire line i'oiiihg Contact may he maintained than at the ends it will assume a barrel shape by applying sufficient Pressure so that all of the due t greater donation at this point and com camber is flexed from the roll; in other'words, the versely' if more rolling is done at the two ends eiehieht oi the '9 at the line of contact with th in t middle greater elongation occurs at the tube is aestraight line. A third condition may these points resulting in a tube having a n be obtained, namely, one in which the greatest mouthed Shana In the ideal u process the rolling pressure is applied to the ends of the tube fibers elongate at the same rate resulting in a by increasing the pressure until it is more than tube of true cylindrical form. However, if the sumcieni to. flex an the camber from the ihtei'hai internal and external rolls are truly cylindrical The external mu may be cambei'ed a tube during the rolling process would tend to if desired develop a bell mouthed shape due to'the fact that gg g zgz i zg zg 8: iai ggg gg ggz gg is the rolls,,and particularly the internal roll, the Eambered mu so that. the point of greatest would deflect an appreciable amount resulting in pressure can be regulated to any position less rolling pressure at the center of the tube than tween the ends of the tuhe at the ends- Other objects and features of my invention Th r llin p ssur al ne th ins y be will be apparent and a better understanding regulated by using one or more rollawhich have thereof obtained by reading t g n m been machined s to have normally a m scription together with the accompanying drawthat is, a curvature upwards from the point of ings of which:

Kreatest pressure with the tube which is the'cor- Figure 1 shows a rolling mill in which a camrect amount of camber to suit. the rolling pressure. bered roll is employed, the internal roll having Theoretically, this camber could be calculated its normal camber. t I

Figure 2 is a transverse section through Figure 1 showing the relative positions of the rolls together with the auxiliary positioning rolls.

Figures 3 to 5 show conditions of the rolls dur- 5 ing different degrees of flexure.

operating the screws 15 by means of which the rolling pressure on the tube is controlled as will be evident hereafter. The bearings 16 for the roll 13 are of the ball and socket type in order that this roll may be flexed without undue strain ,on the journals of the roll.

The bearings 16 are such that the roll 13 may be easily withdrawn for the insertion of the hollow billet 17 which is to be worked. In Figure 2 a pair of auxiliary rolls are shown which support the hollow billet 17 centrally on the roll 12 and means are provided associated with the rolls 18 to permit them to swing outwardly to accommodate for the increase in the radius of curvature of the hollow billet from the rolling process.

During the rolling process, of course, the same pressure is exerted on the roll 12 as on the roll 13 and consequently there is the same tendency for each to flex, but where the rolls are so different in size as those in the modification shown, the flexing of the large roll 12 may be neglected and that only of the roll 13 considered. Of course, the invention is not limited to a case where the .one'roll is flexed, but is sufficiently broad to include cases where either or both are flexed. Since in the modification shown, however, the flexure of the roll 13 need only be considered, this roll has been shown with a cambered surface, that is, one in which the center has a greater transverse cross-sectional area than the two ends. Suitable power means are provided for driving the rolls 12 and 13 at suitable speed, but

as the driving mechanism has no concern with my invention it has not been shown. As mentioned heretofore, the rolling pressure upon the hollow billet is regulated by the screws 15 which bear against the bearings 14 and sumcient regulation is obtained by means of these screws 15 so that the rolling pressure upon the billet may be varied from zero to an amount which is sufficient to flex the roll to a condition where the cambered contour of the surface has been reversed, as shown in Figure 5. Various intermediate stages are shown in Figures 3 to 5. Thus, Figure 3 shows a condition where the roll 13 is slightly flexed but wherein a slight camber of the contacting element of the roll is retained. Figure 4 shows a condition of the roll 13 where sufiicient pressure has been applied to straighten the camber so that the pressure on the billet is uniform. Figure 5 shows a condition where still greater pressure has been applied which is more than sufficient to bend the camber out of the roll and wherein the greatest pressure is applied to the billet at the 'ends.

' The rolling operation. is carried out as follows: The roll 13 is withdrawn and the hot ingot positioned on the roll 12 supported by the auxiliary rolls 18. The roll 13 is-then inserted in the hole of the hollow billet and flrmly secured in its bearings. The rolling operation is then started with the roll flexed to the position shown in Figure 4, that is, with the pressure on the roll 13 regulated to give a straight line rolling contact. This insures even pressure on the ingot. Rolling with this pressure is continued until it is noticed that the tube or billet is not rolling in a truly cylindrical form, in which case the control is regulated to correct the rolling condition, that is, if it be found that the tube is becoming barrel shaped clue to the greater elongation of the tube fibresat the center of the roll, the pressure is increased until the roll 12 is flexed to the condition shown in Figure 5 and the rolling then continued until the tube again assumes a true cylindrical shape at which time the pressure may be decreased so that the roll 12 again assumes the straight rolling condition as shown in Figure 4. On the other hand, if the rolling is pioceeding so that the tube is becoming bell mouth shaped at the ends, the pressure on the bearings 14 may be decreased by means of the screws 15 until the roll 12 assumes the shape shown in Figure 3, that is, having a slight camber existing which is sufficient to apply the greatest pressure at the middle of the roll. Thus by properly operating the machine, in accordance with the invention,-a true cylindrical seamless tube or cylinder may be manufactured. I 105 Another embodiment of the invention is shown in Figure 6. This embodiment is particularly desirable where long lengths of tubes are to be rolled and where difficulties may develop which would be hard to correct unless itv were possible to shift the point of greatest pressure along the length of the tube. By cantingeither or both of the rolls the normal to the surface of the cambered roll at the point of contact with the tube is shifted at will along the length of the tube. This normal point is also the point of greatest pressure. In the modification shown in Figure 6, the main or lower roll 12 is the one which is adjustable. The normal position of the roll is shown in full lines while the dotted lines show the roll 12 in one of its canted positions, that is, the axis of the roll has been shifted from its position SS to the position S'S'. Of course, this is only one position which the roll 12 may assume as it is also possible to shift the roll in the other direction, so that the point of greatest pressure may be adjusted to any position intermediate the ends of the tube.

In describing this invention several embodiments have been shown but many others will at once suggest themselves to those skilled in the art within the spirit of the invention which is to be limited therefore only by the prior art and the scope of the appended claims.

I claim:

1 A machine for the manufacture of tubes or hollow bodies by internal and external rolling comprising a main roll, a second roll having a normally cambered surface and means for changing the symmetry of the cambered surface during the rolling process.

2. A machine for the manufacture of tubes or hollow bodies by internal and external rolling, comprising a main roll, a second roll having a normally cambered surface and means for changing the said cambered surface adjacent the element being rolled during the rolling process.

4..A machine for the manufacture of tubes or hollow bodies by internal and external rolling comprising a main roll, a second roll having a normally cambered surface, bearings for said main roll and means for exerting pressure on the said main roll during thevrolling procew to effect a change in the symmetry of said second c'ambered roll.

5. A machine for the manufacture of tubes or hollow bodies by internal and external rolling comprising a main roll for supporting the tube blank and means effecting constant rolling pressure along an element or said blank, said means comprising a normally cambered roll adapted to be flexed so that the element of the cambered roll contacting with the tube blank is a straight line.

6. A machine for the manufacture of tubes or hollow bodies comprising a roll adapted to support a tube blank, a cambered roll adapted to contact with said tube internally, means for exerting rolling pressure on said tube and for flexing said cambered rolfwhereby the curve at the line of contact of said cambered roll may be diminished or reversed.

7. A machine for the manufacture of tubes or hollow bodies comprising a main roll and a cambered roll and means for varying the angular relation between the axes of said rolls.

8. A machine for the manufacture oi tubes or hollow bodies comprising a main roll and a cambered roll and means for canting the main roll with reference to the axis of the cambered roll.

9. A machine for the manufacture of tubes or 'hollow bodies comprising a main roll for supporting a hollow tube blank, a cambered roll positioned internally of the tube blank, between which rolls the tube is adapted to be rolled, and means for varying the angular relation between the axis of the cambered roll and the axis of the tube blank.

10. A machine for the manufacture of tubes or hollow bodies comprising a main roll for supporting a hollow tube blank, a cambered roll positioned internally of the tube blank and adapted to apply a rolling pressure to the tube together with the main roll and means for canting the tube blank with reference to the axis of the cambered roll. v

- ROBERT K. HOPKINS. 

